Circuit interrupter



April 24, 1951 R. s. BENNETT ET AL 2,550,444

CIRCUIT INTERRUPTER Filed March 17, 1950 lnvenToPs Ralph S. B nne Charles F. Passe, 3

Their Airo Patented Apr. 24; 1951 CIRCUIT INTERRUPTER Ralph S. Bennett and Charles F. Passe, Pittsfield, Mass, assignors to General Electric Company,

a corporation of New York Application March 17, 1950, Serial No. 150,278

1 Claim. 1

This invention relates to electric circuit inter- Tupting devices and more particularly to a new and improved arrangement whereby a load circuit in which such a device is installed may be manually opened While under load.

In the case of a conventional fuse cutout type of device this function may be carried out by the employment of a switch stick to disengage a movable contact on the device from a stationary contact, However, when the load on the circuit is of sufliciently high magnitude a long arc is thereby drawn and under these conditions harmful fiashovers between adjacent parts frequently occur. To overcome this contingency, fuse cutouts have been furnished in connection with which an arrangement is provided whereby the lineman can exert a pull on the fuse link where it extends out of the bottom open end of the fuse tube and break it, so as to interrupt the load inside the fuse tube in a manner similar to a normal fuse blowing operation. Obviously, this is a much more effective way of interrupting the load current than is the method of disengaging separable contacts. Nevertheless, the utilization of such arrangements usually result in the imposition of unwanted stresses on the cutout structure and, insofar as is known to applicants all such arrangements have involved the employment of additional linkages or levers as a result of which the device has become more complicated and costly.

It is, therefore, an object of this invention to provide an improved fuse cutout incorporating structure which will permit the manual interruption of a circuit while under load.

It is a further object of this invention to so embody this structure that the necessity of additional parts in excess of the parts presently embodied in existing and similar cutouts will be eliminated.

In accordance with this invention, we provide a portion on the support for an. expulsion type fuse tube which is sufliciently spaced from the part of a fuse link conductor which extends transversely out of the open end of the tube to permit the insertion therebetween of the hook portion of a conventional switch stick. In addition, this portion of the fuse tube support is provided with a projecting portion which overhangs the transversely extending conductor a predetermined distance so as to serve as a reactive support pointfor the upper surface of the switch stick hook when it is swung laterally with respect to this portion of the support.

The invention will be better understood from the following description when taken in connection with the accompanying drawing and the scope of the invention will be pointed out in the appended claim. In the drawing, Figure l is a side elevation, partly in section, of a fuse disconnecting switch or cutout embodying the invention and shown in the circuit closed position and Figure 2 is a section taken on the line 2-2 of Figure 1.

Although the invention is equally applicable to the enclosed type of fuse cutout, we have shown, for the purpose of illustration, an open type fuse cutout in which the numeral Ii) identifies a main support of porcelain or other similar insulating material of a size and shape used in connection with the fuse cutouts of the prior art. Insulating support It may be suitably supported from a pole, not shown, in a conventional manner, one manner of which is by a supporting arm or bracket l i one end of which is cemented internally within the support It. Adjacent one end of the insulator l 0 and supported therefrom so as to extend transversely of the insulator is a first relatively stationary contact means [2 in conducting relation with a terminal I3. Supported from the other or lower end of the insulator in line with the longitudinal axis thereof is a hinge means or hook type bearing member M. A second relatively stationary contact means IS in con.- ducting relationship with a terminal I6 is suitably mounted on bearing member l4. To serve as a support for an expulsion tube ll a hinge element I8 of conducting material is provided havfing trunnions I9 adapted to be inserted in the hooks 29 of the bearing element l4. Hinge element or support is is also provided with a contact 2i movable into and out of engagement with contact means I5 upon rotation of the hinge element. For completing a conducting path between the stationary contact means l2 and I5 and consequently the terminals l3 and it, a current conducting means is provided and comprises a conductor 22 having a portion 23 fusible at a predetermined value of current. Conductor 22 including fusible portion 23 which is also relatively weak mechanically is mounted within the expulsion tube IT with one end of the conductor suitably connected electrically to a conducting cap 2 1 threadingly mounted on the upper end of tube I? and engageable with stationary contact means l2. As shown, the tube I7 is directly secured by a clamp 25 which in turn is pivotally mounted at 25 on the hinge support element 18 constituting therewith a toggle which is held in the rigid condition shown by pulling the end of conductor 22 which extends out of the bottom open end of tube ll transversely thereto toward a portion of hinge support i8 which is laterally positioned with respect to the expulsion tube where is it secured in any suitable manner such as clamping it between the hinge element and a nut 2? which may be drawn tight by a screw 28. For main taining the switch in the closed circuit position shown in the drawing, there is provided a holding means which may be of any conventional type such as the one illustrated which comprises a U-shaped resilient member 2d, the outer ends of the legs of which are bent inwardly and then outwardly to provide, in V-shaped formation, flared ends which yield sufficiently to permit entrance of contact cap 2,4 and thereupon close over the cap to prevent reverse movement. U-shaped holding member 29, terminal l3, leaf contact spring i2 and, in addition, a leaf backing spring l2 are all carried by a bracket 30 extending ou+- wardly from insulator iii and supported therefrom on a stud 3i mounted in the insulator.

The fuse tube i1 is made from or is lined with a material which will give off an arc extinguishing gas when subjected to the heat of an arc. Consequently, in the event of a current through conductor 22 in excess of the rating of fusible element 23, this portion will rupture whereupon the lower portion of conductor 2'2 will begin to drop downwardly through tube ll thereby establishing an are which will promptly be extinguished by the gas given off from the tube. In this manner, the portion of the circuit in which the device is installed may be opened or automatically isolated from the balance of the system as is well known in the art. In addition, the switch may be manually opened by inserting the hook portion 32 of a switch stick 33 in an operating eye 34 mounted on the fuse tube 17 to separate movable contact 24 from stationary contact I2. However, as previously pointed out, this sometimes results in a long arc being drawn between these two contacts which is difixcult to extinguish and which may flash to adjacent parts or equipment with adverse results.

Therefore, to manually open the device and at the same time realize the benefit of the are extinguishing gas given off by the fuse tube IT, we have provided an improved means whereby the conductor 22 may be manually broken at the fusible or relatively mechanically weak section 23 within the tube. This means comprises a web portion 35 of support casting i8 which extends from the laterally positioned portion thereof toward the expulsion tube IT. This portion may be joined, as illustrated, or may not be joined with the upwardly extending portion 3% of support 68. It should be noted, however, that web 35 is sufliciently spaced from the portion of conductor 22 which extends transversely from tube [1 so as to permit the insertion therebetween of the hook portion 32 of switch stick 33. It should furthermore be noted that in accordance with this invention extending web portion 35 defines a surface which projects transversely or laterally to the general direction of extension at predetermined distance, the dimension of which, as better illustrated by Figure 2, may be in excess of the corresponding dimension of other portions such as 31 and 38 of support l8. In other words, web portion 35 projects suificiently so as to substantially overhang the transversely extending portion of conductor 22 as better illustrated by Figure 2. Thus, surface 39, or the edge thereof, of projecting portion 35 serves as a support fulcrum for the upper surface of the hook 32 whereby the handle of switch stick 33 may be pulled or twisted sideways by a lineman to exert a generally downward force on conductor 22 sufficient to break it at the mechanically weak section 23 within the expulsion tube. Inasmuch as the force on conductor 22, tending to impose a stress on the device, is opposed or neutralized by the reactive force on projecting element 35, it will be apparent that there will be no tendency to overstress the upper terminal support 3!! or disengage movable contact 24 from holding means 29 as might be the case if a vertical pulling force, instead of a twisting force, were exerted on the handle of the switch stick 33.

We have thus provided an improved means whereby a fuse link conductor may be manually broken within an expulsion tube which means is not only effective but is simple and inexpensive in that no additional member, movable or otherwise, has been incorporated as a part of this means.

While we have, in accordance with the patent statutes, shown a particular embodiment of our invention, other changes or modifications will be obvious to those skilled in the art and we, therefore, aim in the appended claim to cover all such changes or modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

an electric circuit interrupter comprising an expulsion tube ng a contact at one end thereof, opposite end of said tube being open, a hook type bearing member, a hinge element, said tube mounted on said hinge element, said hinge element having aportion lateraily positioned with respect to said expulsion tube provided with trunnions adapted to be inserted in the hooks of said bearing conductor having a mechanically weak section mounted in said expulsion tube with one end of the conductor connected to said contact and the other end extending out of said open end of said tube transversely to the longitudinal xis thereof toward said laterally positioned poi of said hinge element and secured thereto, said laterally positioned portion of said hinge element having a web portion extending normally with respect to the axis through said trunnion toward and engageable with said expulsion tube, said web portion being sufficiently spaced from said transversely extending conductor to define a free space therebetween for the insertion therein of the hook portion of a switch stick and defining a surface projecting transversely to and a predetermined distance from a plane passing through said tube axis so as to substantially overhang said conductor and normal to said trunnion axis to serve as a fulcrum for the hook or" said switch stick to permit the application of a force through a lever arm to said transversely extending portion of said conductor whereby said conductor may be manually broken at said mechanically weak section.

in ember, a

RALPH S. BENNETT. CHARLES F. PASSE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,493,432 Yonkers Jan. 3, 1950 2,493,433 Yonkers Jan. 3, 1950 2,514,163 Pittman July 4, 1950 

